Telephone system



. IDE

5 sheets-sheet l f Y .ini/F2727?? Harry/ZEE'.

Mar. 27, 1923.

' H. IDE

TELEPHONE SYSTEM Filed Feb 14 1919 5 sheets-sheet'J 2V Kw www LBR MNMUNE.E

ot a call from substation A., to automatically connect with an idlelirst selector C as shown in Fig. l, part l. The subscriber at A, bytheuse of the calling device in connection with his substationequipment, may by its actuation, operate the iirst selector C to extendthe connection Jfrom the said substation A to an idle connector, switchD. The subscriber at A then, may by further actuation of his callingdevice, operate the connector switch D kto connect with the terminals ofthe called-tor line E. It the called line is idle, ringing current isautomatically applied to the terminals thereoi' `to signal thecalled-for subscriber. Should the line of the called for subscriber be`busy, a characteristic busy signal will .be automatically transmittedback to the calling subscriber who `-may by replacing his receiver uponits switch hook release the switches which were used in extending hisline to the line ot the :called- 'for subscriber.

The switch B, as dia-grammatically illustrated, comprises a double-woundline and test relay LR, a single-wound*,cut-off relay CO, and a motormagnet MM. The line relay LR is adapted to be energized 4over the twosides of the subscribers line in series, the cut-olf relay CO is adaptedwhen energized to disconnect the subscribers line circuit from the linerelay LR., and to connect the switch wipers to the subscribers linecircuit, providedthe line switch B is bein?? used for calling purposes.The motor magnet Mil/l is provided for stepping the switch sliatt andwipers 2, 3 and el step by step over the bank contacts 5, 6 and 7. Theswitch wipers 2, 3 and el are adapted to always be rotated in the samedirection and do not restore to normal, that is, the switch wipers do'not have a normal position, but remain in their antecedent progressiveposition when a connec" tion is released. The wipers 2, B and Il aredouble-ended wipers and as one contacting end of these wipers moves oitthe last contacts ot their respective switch banks, the other contactingends thereof move onto the first contacts of the switch banks. The otl'-normal .contacts ON are so arranged that when the line relay LR isenergized, they are moved to their oil-normal position and are returnedto their normal position by the energization of the cut-ott relay GO,that is, these off-normal springs are so arranged that when the linerelay LR is energized a catch mechanism is koperated to release theoff-normal springs to their operated position, and upon the energizationoil" the cut-oft relay C() the springs are returned to their normalpositionin whichposition the catch mechanism again 1s brought intooperation to hold the' oifnormal springs in their normal position.

The .switch shaft which carries wipers 2, 3 and 1- 1s providedvwith aratchet mechanism which is adapted to cooperate with the driving pawlcontrolled by the motor magnet lVllll to rotate the switch shaft andwipers in a clockwise direction.

A further mechanical arrangement is provided for the line switch andconnects the line relay LR and the cut-oil:1 relay CO in such a mannerthat the armature of the cutotl' relay CO can not befully attractedunless the line relay LR has ,been energized lirst, that is, ir" theline relay LR has been energized the armatureof the cut-ott relay CO maythen be energized to move its switch contacts to their alternatepositions into engagement with their alternate contacts, while it' thecut-ofi' relay CO is energized before the line relay LR' is operated,the armature oi the cut-ot relay is permitted to move only a sulicientdistance that its contacts 9, 1() and 11 are moved from engagement .withtheir back contacts 12, 18 and 14, respectively, but not into engagementwith their front contacts 15, 16 and 17. This feature is provided sothat when the substation A is called from a connector switch and thecut-ori relay CO energized, the subscribers line can be disconnectedfrom the line relay LR ot' the switch B, but cannot be connected withthe switch wipers of the switch.

Referring now particularly to Figs. 2 to 7, inclusive, l illustrate thecut-ott relay CO and its associated mechanism in its various operativepositions, and in Fig. 2 illustrate the cut-ott' relay CO in itsnormalposition, in which its armature 106 is in its retracted position and itsassociated contacts L in their normal position, and in Fig. 3 I show theoff-normal contacts ON in their normal position andmounted on theextension 10412 of 'the heel iron 10a of thecut-otf relay CO, and themovement ot the off-normal contacts 0N is jointly controlled by the linerelay LR and the cut-orf relay C0. An armature shaped member 116 vispivotally supported at the 'forwardend oi the extension 10112 byv meansot a suitable pivot pin, which pin also pivotally supports the armature106 of the cut-off relay CO. A. bracket 1 24Lsuitably secured to themounting plate, pivotally supports a latch 126, and the leg 128 of themember 116 is provided with a shoulder 129, which rests in a notch 130in the latch 126. The edge 131. of the said `shoulder 129 engages theside132 ot the notch 130', retaining the member 116 in its position asillustrated in Fig. to hold the voil-normal cont-acts ON in their normalposition.

' iln arm 141" secured to the armature 106 ot the relay CO isoperatively associated with a latch 143", which latch 141-3 is alsopivotally supported by the bracket 1241 and is also operativelyassociated with the leg 128 ofthe member 116', the saidlatch 143 lyingadi acent to and parallel with the latch 126. The latch 1113 is providedwith a When :a cali. is initiated the line relay'LR is energized and itsarmature is attracted, and the angular arm 145 secured tothearmature ot'the relay LR is moved in an upward direction and engages the extension1262 of the latch 126. lthis causes the latch Y Y I l Number 175,364,iledilunelS, 1917. lt'is to be understood, however, that the circuits-126 to be raised, and when the face `132 of the notch 130 passes beyondthe edge 131 i oi' the shoulder 129 ot' the member 116', it releases thesaid member 116, allowing` it to rotate about its pivot and permittingthe oitnormal contacts DN to assume theirl alter` nate position, asillustrated in Fig. 5. When 126 rests uponthe edge 147 ofthe shoulderThe latch 1 3fis also raised dueto the extension 1262 passing under thelatch 143 so that when the latch 143 is inthis position, as illustratedin Fig. 4, the arm 141 is clear of the notch 144 in the forward yend ofthe latch'143. The positions of the latches 126 and 143 when in theiroff-normal position are illustrated in Figs. 4 and and the shiftedoil-normal contacts C@ in Fig. 5. After selection thecut-oii relay COcnerq'izcs to attract its armature 106, ifollowed yby thede-energization ot the line relay LR, andthe attracted armature 106carries the arm 141 with it and in its movement engages the member 116and again rocks itabout its pivot. The line relay LR- upon restoringallows the arm' 145 to disengage fthe extension 1262 of the `latch 126and the the edge 132 of the notch 130, the off-normal contacts ON arelocked in their normal position yuntil another engagement of the linerelay lill. The cut-oil` relav C@ energizing' shiits the springs li totheir alternate positions and thc latch 1.43 `is in such 'a positionthat its bottom edge 146 rests on the upper edge 149 of thearm 141', asclearly illustrated in Fig. 6. "Upon the restoration citent-ofi' relayC0, its armature retracts, the arm 141 moving therewith so that when itsedge 150 passes the edge 151 1 of the notch 144 of the latch 143., thesaid latch 143 rocks on its pivot and again allows `the arm 141 to restin the notch 144 o'fthe y latch 143.

`New, should the line associated with the cut-off relav CO be a calledline, the said cutoii relay C@ will'be'energized, butdue to the arm 141resting in the notch 144 of the `latch 143 ig. 2), the movement ot thearmature 106 is limited by the amount of play that the arm 141 has inthe notch 144.

rlhe circuits shown for the selector switch C and connector switch D areadapted to worlr with a switchstructure similar to that shown in mycai-pending` application, Serial may be used in connection with variousswitch structures o1' the art.

The iirstselector -C lcomprises ran impulse relay 1R, which relay isenergized and dep energized by impulses from the calling dein thisposition the edge 146ioi the latch' vice CD at the calling substation A,and the energization and de-energization of the relay llt brings aboutthe actuation of the `primary magnet PM to step the iirst selectorswitch wipers 209, 210 and 211 in a primary direction to .a certainO'roup ot contacts. A secondary magnet Sli is provided for said selectorwhich automatically steps the wipers 209,l 210 and 211 in a secondarydirection over the contacts 220, 221v and 222 in the selected` groupy toseek an idle set of contacts leading,- to a connector, as D. A switchingrelay 'll is also provided which, when enerf gized, extends theconnection or" the 'calling substation A tothe idle connector D. Primaryand secondary oil-normal contacts PGN and SON, respectively, areprovided.

llhe said primary oi-normal'contacts PON assu-me their alternatepositiononthe iirst `step of thewipers in a primary direction,

and the secondaryof-normal contactsSON assume their alternate positionupon the iirst ste-p ot the wpersin a secondary direction.

vThe connectorswitch D is provided with an impulse relay IR, responsiveto the impulses ot' the calling device CD at the calling substation A,which relay 1R brings` about the actuation of the primary magnet PM tostep the connector switchy wipers 235, 236 and 237 `in a primarydirection` to a certain group of lcontacts containing' contacts of the`called line E. A switching'relay S117 is pro-` vided which energizesupon the termination of the first set of impulses to connect thesecondary magnet SM in circuitwith the impulse yrelay IR", to beactuated bythe cn- `ergization and the de-energizzationy thereof to stepthe connector switch wipers 235, 236, and-237 over the contacts 250.vand 252 in `the selected group to seek the contacts of the called line.y

, A test relay TR is also provided which is actuated to test the busy oridle condition of the called subscribers line'. Thesaid test relay TRoperates to connect the busy back apparatus .lto the calling subscribersline 'to notify `the calling subscriber of the busy `condition of thecalled line.v A ring' controlA scribers li-ne from the ringing current,generator Gf.; A back bridge orsupervisory relay SH is also providedwhich operates upon the response oi the called subscriber and controlsdisconnection orv prevention ot further applications of ringing currentto the called subscribei"s line. Primary and secondary ott-normalcontacts PGNA and SON are provided to :.issnineftheir alternatepositions, respectively, Vupon the movements ot wipers 235, 236 and 237.y

To the right of Sheet substation E similar to substation A, the saidsubstation E being connected to a line switch Having described ingeneral tiie structure i of the switches and apparatus, lr will now.

at the exchange similar to line switch B.

explain more in detail the operation ot' the same.

Assuming that a call is to be traced from the calling substation A tothe called sul station lil, upon the removal ot' the receiver by thesubscriber at the calling substation A,

I line rela f LR of switch l is energized b current traced frombattery,through the upper winding oct relay Llt, contact 100 ot motormagnet MM, normal contact 101 ot' olinormal springs ON, contacts 111 and11 of relay CQ, through the calling substation baclr potential.

through contacts 9, oi" relay C() and through the lower winding of relay11R to ground. Line relay LR upon energizing` trips the ott-normalcontacts ON to their operated position. ris before mentioned,

wipers` Band @always rest upon the set ot contacts 5, G and 7 last used,and assuming the contacts upon which the wipers now vrest are busy, dueto another subscribers line switch having selected the first selectorlast used by the subscriber E1, the engaged pri.- if'ate contact will befound -toV contain a busy rl`he tripping ot off-normal contacts ONconnects the upper winding ot line relay LR tothe private bank contact5,

which we have assumed contains abusy potential.` over a circuitextending from batteiy, through the upper winding of relay LR, normalcontact 100 of motor magnet MM, alternate cont-act 101 of olf-normalsprings ON, contacts 13 and 10 of relay CO, to private wiper 2 and thegrounde-d'pbanlr Contact The line relay will thus remain' energizeduntil its circuit is opened at contact 100 ot the motor magnet MM. Theclosure of Contact 102 of relay LB closes a cir' Vmagnet lilM andpermittingr the said motor magnet MM to restore. Should the contacts nowengaged by the wipers be busy, relay LR energizes by current throughnormal contact 100 ot' motor magnet MM and again closes contaet102,energizing motor magnet MM, before` described. Theline and test relayLR' and magnet MM are thus alteri nately energized anddefenergized,magnet 2,1 show a called MM stepping wipers `2, 3 and 4 from one set .ofcontacts to the next as long as busy, that is, as long as groundedcontacts are encountered, and relay LR energizing each time a groundedbank contact is encountered. yMagnet MM alternately opens and Aclosesits contact 103, andithus a vibratory circuit is closed through thewinding ot vcut-off relay C@ to ground, through contacts /1ot'yoff-normal contacts ON. The winding of relay C@ is of highresistance and as motor magnet MM e-nergizes and deenergizes with greatrapidity, the said winding ot relay C@ does lnot effectively energizeand attract its armature while the mo-r tor magnet MM is operating. Therelay CO may. also contain a copper sleeve to maire it slightly slow toenergize. Closure of contacts 10401 orf-normal contacts ON places 9battery, through the winding of relay CO, y contact 103 or' motor magnetMM, and contact 10% of off-normal contacts ON to ground. Relay CO uponenergizing restores the oil-normal contacts ONto their normal positions,connects the subscribers line to linewipers 3 and 4 and connects thesaid winding of relay C@ tofprivate wiper 2. The relay CO lbeing slow'to release is held .up momentarily until a substitute circuit isestablished for therelay CO, ras will be presently described.

' The connection ot' the subscribers line to line wipers 3 and 4l ot theswitch B closes an energizing circuit for impulse relay 1R Aotthe'idlefirst selector C over a circuit 194 and through relay R toground.

Closed alternate contact 195 otrelay IR energizes relay 196 by currentfrom' battery, through the upper winding of relay 196, contact 195, toground at normal contact 199 ol' the primary oll--normalcontacts PON.Relay 200 is now energized, from battery through the upper 4\\f'iiniling ot said relay 200, alternate contact 19(5to grouiul at norHmal rentar-t 199. The closingot alternatey contact 201. of relay200establishes a substitute energizing circuit itor'relay C() ot the lineswitch (l beto t `has had time to (lc-energize, said circuit being`traced 'from battery through relay CO, normal contact 1023, Wiper 2,contact 5, conductor 203, alternate Contact 2041, to ground at alternatecontact 201. `Relay C() remains energized until time o1 release. Theconnector contacts 1.07 e111 are also made `busy by the grouinl justtraced.

It" the private contact engaged by the wiper 2 idle when the subscriberA initiatesa call, the line relay LR is energized as before described,and contacts ON assume their alternate position, but the closing otcontact 102 ofrelay LR does not energize magnet MM since there is noground on Contact@ and the magnet Mil/l remains inert. rlhe cut-oilrelay UO is iinniediately energized Ito ground atfcontact 1,01-,restores contacte UN as bel'iore described, and the relay C@ is heldenergized over lthe circuit to ground att), as already described. 'lhusswitch l only travels when its wipers are in engagement with a busytrunk when a call is initiated.

11n idle first selector C having been seized as just described, andassuming that the number oit the called substation E is 3115, thesubscriber It actuates the calling device CD to send three impulses otcurrent over the line, which impulses bring about three rapidile-energizations and energizations or` the impulse relay 1R. Theprimary magnetPll/l is energized and cle-energized three times, due tothe closing and opening of normal contact 195 olf relay IR (circuitbeing traced Via 20G, 20T, 195, 208) which magnet operates to step thewipers 209, 210 and 211 oit the first selector C in a downward primarydirection to the third group oi? contacts, thus selecting thethree-hundreds group ot connectors. Alter the last impulse, the relay200 de-energizes, due to a circuit being closed through the lowerWindingl of the said relay 200, normal contact 212, alternate contact21?` of relay iR, and alternate contacts 2111 and 199. The said primaryoit-normal contacts PON moveto their alternate'positions upon therststep of the Wipers ot the first selector D, and the energizing circuittor the lower Winding of relay 200 just mentioned is closed upon theiirst step o1? the wipers oit normal, but the relay 200 does notde-energize during the sending oit impulses, it being differentiallywound and only re neutralizing winding during, the iin se operation o'lrelay llt. As soon ceivino` short impulses ojl current through itsaboyejmentioned circuit through the lower winding of relay 200 issteadily closed, the

` lower or neutralizing Winding builds up and are transmitted throughits lower or neutralizing Winding ydue tothe construction and adjustmento1 the said relay 196. Upon the de--energization of the relay 200, anenergizing circuit ior the relay 215 is established from battery,through normal contact 216 of relay T, normal Contact 217, normalcontact218 of' the secondary olli-normal contact SUN, normal Contact 201,alternate contact 204i to `ground at 199, and relay 215 energizessecondary magnetvSM by current from battery through said magnet SM toground at contact 219. Secondary magnet SM steps the Wipers 209, 210and211 one step in a ro# tarf or secondary direction` to engage the lirstset of contacts 220, 221 and 222 and the opening of normal contact ,217at magnet Sli/l cle-energizes relay 215. Contact 212 opens the circuitof the lower Winding of relay 200 which energizes again. Relay 215 opensContact 219, cle-energizing secondary magnet SM. Upon the v irst step ofthe Wipers 209, 210 and 211, the secondary offnormal contacts SON assumetheir alternate position, opening the initial energizing circuit oi' therelay 215, and should the private iyiper 209 of `the, first selector Dengager a contact leading to a busy connector, a substitute ycircuit isestablished for relay 215 traced from battery through the Winding of therelay 215, normal contact 216, normal contact 217, alternate contact223, alternate contact 2211 and Wiper 209 to the grounded busy Contact220. The resulting closing of contact 219 again energizes secondarymagnet SM. The relay 215 and magnet SM are thus alternately energizedand cle-energized to step the Wipers 209, 210 and 211 in aiseeondaryrotary direction to seelr the contacts olf an idle connector switch asE. lVhen a contact 220 leading to an idle connector is encounteredby theWiper 209, an energizing circuit of the relay 215 is not again closed,and no further energizations of the secondary magnet SM occur. By thissee-saw action of relay 215 and magnet SM av positive driving operationof the secondary magnet SM is securedand the selector C Willnot stop ona busy contact or go past an idle con-r tact because unless relay 215 isenergized, mami-et cannot be energized, and relay 2153 can only beenergized when magnet SM Ais at normal and' `private wiper 209 'isrestingon a busy contact. The relayy 200 does not cle-energize duringthe secondary movement ot the wipers, due to its adjustment and therapidity of the interruptions of contact 212 of 'secondary magnet SM.The steady closure ot Contact. 212 of magnet SM after its lastCle-energization closes a circuit for the lower winding of the relay200, as previously described, and due' to' its differentialvconstruction, it cle-energizes, whereon van energizing circuit for. therelay T is established traced from battery through the winding ofthesaid relay T, alternate rcontact 218 of' the secondary olif-normalcontacts SON, normall contact 201, contact 204 to groundat 199.` Theopening otnormal contacts 192 and 193 of relay T opens the energizingcircuit of the impulse relay 1R, and the closing of normal contact 195of said relay 1R' closes a circuit through the lower winding ofthe relay196 traced trom battery, through the said lower winding, normal contact195, to ground at contact 208 of relay 196', which relay 196, due to itsvdifferential winding, neutralizes and restores to normal, and 196'opens the circuit' of relay 200 permitting' the latter to restore. Theclosing o1" alternate contacts 192 and 193 ot relay T extends theconnection of the calling subscriber A to the idle connector D,engagedby wipers209, 210 and 211 of the first selector'C, bringing aboutthe energization or' the impulse relay 1R' of connector D over a circuittraced from ground through one winding ofthe relay IB', contact 222,wiper 211, alternate contact 193, contacts 7-4, alternate cont-acts17-11, through the substa- `tion A, alternate contacts 12-15, contacts3&6, alternate `contact 192 wiper 210, contact 221,and throughthe lelthand winding ofthe relay 11i/to battery and ground. The restoratio'notthe relay 196 of the irst selector Copens the initial energizingcircuitot relay Tat C, but the relay T being slow to release has asubstitute circuit established or'it, traced from battery through thewinding 'of said relay, its alternatey contact 225, wiper 209, bankcontact 220, conductor 226, and conductor 227 to ground at alternatecontact 228 o'l' the impulse relay 1R'. The said relay T remainsenergized until the termination of the conversation.

The energization of the relay 1R' energizes relays, 229 and 230, thecircuit ot relay 229 extending from battery through the right handwinding of said. relay, normal Contact 231 ofthe primary off-normalcontacts PON', conductor 226 and conductor 227 to groundat alterna-tecontact 228 ot relay IR'. A circuit is also closed through the lowerwinding of relay 230 upon the energizat'ion of relayl'R extending frombattery through the lower winding of the relay 230, conductors 231', 232and alternate contact 233 to groundy at alternate contact 228 of' relay1R'. However, the relay 230 does not opera-tively energize at thisr timeowing to the fact that the energization of relay 229 closed a circuitthrough the upper winding of relay 230 and at the time relay 229energized. The windings of relay 230 being wound diiferentially,prevents the relay operatively energizing. Relay 229 locks itself togroiuid at 234. Four impulses now transmitted from A de-energize andenergize relay 1R tour times causing the primary magnet PM to energizeand de-energize tour times to step the wipers 236 and 237 in a downwardprimary direction to the fourth group oft contacts containing those ofthe called line. Upon the first energization of relay I t', the circuitthrough the lower winding of relay 230 is opened, thereby permit-tingthe same to immediately energize. kr1`he circuit of the primary magnetPM may be traced from battery through the winding of the said magnetBM', normal contact 238 of switching relay SW, conductor 239, alternatecontact 240 ol relay 230, normal contact ot relay 1R', conductor 227,conductor 226, through normalI contact 231 or the primary oit-normalcontacts PON to ground at alternate contact 234 of relay 229. After theprimary off-normal contact 231 assumes its alternate position, whichoccurs upon the first step of the switch shaft, the ground ted fromcontact 241 of relay 242* is substituted. for the ground ted throughcontact of relay 229. After the last impulse of the series has beensent, the steady ilow of current through bothwindings of' relay 230causes the said relay 230, due to its dili'erential action, toneutralize and restore its contacts to normal, but it does not restoreduring the sending of impulses due toits adj ustn'ient, construction andthe rapidity ot the interruptions of contact The closing ci' normalContact l243 or' relay 230 energizes switching relay SW' by currenttlirough the winding of said relay SW, its malte-beforebreal; contact244, normal contact of secondary oli-normal springs SUN', conductor 246,normal contact 243 of relay 230, and conductor 247 to ground atalternate contact 248 ot' lprimary oil-normal contacts PON', and relaySV locksitself to ground via contacts 257r and 248. rhe closing otalternate contact 23801 the'switching relay i 51W merely substitutessecondary magnet SM" for magnet PM', so that when the calling subscriberat the substation A sends the last set oi' impulses,which we haveassumed are livev in number, relay 1R' energizes magnet SM five times,and secondary magnet SM' steps the wipers 235, 236 and 237 in asecondary rotary direction to engage contacts 250.v 251 and 252 of thecalled line. Upon the iirst impulse of the last set,- the relli lay 280again energizes to permit thev secondary magnet SM to be operated, andatter the lastv impulse the relay 230 is again deene1.gized, aspreviously described, and. close-3 a circuit for the test relay TRtraced trom battery, through the Wind-ing ot the said relay, conductor25B, the alternate contact 254, alternate contact 245, ot the secondaryoit-normal contacts SON, (said contacts haring been moved to theiralternate position upon the lirst step of the wipers in their secondarydirection), conductor 246, normal contact 243, conductor 24:7 to groundat 24:8. The closing ot alternate contact 255 oli relay TR connects thesaid relay over conductor 256 to the test or private wiper L85, andshould the called line be busy the private contact 2:10 of the calledline would be grounded, thus closinga locking circuit 'tor the saidrelay TR through the private Wiper.

CaZZecZ Zinc idle.

Assuming that the called line is idle, private contact 250 ol the calledline will he tree of ground, and the relay TR will not remain energizedbut will fle-energize. The ,opening ot normal contact 257 of relayTR'upon its momentary energization opens the circuit ot the switchingrelay SW ,and the relay SW (le-energizing` opens the circuit tor relayTR at its contact 254, leaving the relayTR de pendent upon the potentialfound upon the private contact 250 of the called line. Since,`

262. The closing of alternate contact 263 oit.

relay 242 short circuits the lower Winding ot' the said relay, and theclosing ot its alternate contact 264 closes a circuit through the upperWinding of the said relay through the alter nate contact 26a andconductor 261 to ground at 262. The relay C0 of the line switch Bassociated with the called line E attracts its armature but its movementis limited, as previously described, but this movement allows contacts177 and 178 to assume positions to remove the substation control ot theline switch B of the called line E. The other contacts oft the relay COare not at'- iected due to this limited movement." f i The closing otalternate contact 265 o't relay 242 connects the interruptor I of therelay 266. circuit tor relay 266 being traced trom battery through relay266, conductor 267, alternate contact 265, conductor 268,

normal contact 269 "and through l to ground.` The relay 266 is thusintermittently energized and de-energized, and uponeach(le-energization` ringing generator is connected to the called line overa circuit extending from the ungrounded pole ot' the generator Gr,

relay 266 is energized, a circuit for the relay SR is closed, frombattery through the lower winding oit the relay SR, through alternatecontact 27a of relay 266, Wiper 287, contact 252, throughthe now closedupper `contacts of the substation lswitch hook at the called substationE, back through contact 251, Wiper 236, alternate Contact 275 of relay266, and through the lupper Winding of the relay SR togroun'd.y Therelay SR, upon energizing closes an energizing circuit tor the ring ingcontrol relay RC, Which maybe traced from battery (through the Windingof the said relayPtC, its makebefore-break contact 277, to ground at278. Contact 279 loclfs relay RC from battery, through the Winding ofthesaid relay RC, its alternatecontact 279 Iand conductor 247, to ground atalternate `contact 248 ot the primary olf-normal contacts PON. Theopeningof normal contacts 269 and 270 disconnects the interrupter I andthe ringing generator Gf to prevent further application of ringingcurrent. A substitute circuit tory the relayy 266 is now establishedwhich may be traced from battery, through the Winding ot the relay/266,conductor 267 alternate contact 265,`conductor 268, alternate contact-269 and conductor 424C? to ground at 24:81 The subscribers are now inconver-` sational circuit, and thetalking circuit may be traced over theheavily marked conductors, said conductors having the condensers 1 l andK2 interposed.

Release.

tact 216 of relay T energizes relay 215 by current Ytrom battery,through said relay 215,

normal contact 216,; normal contact 217, normal contact 223 and contact21e, to ground at 199. The closing et' alternate contact 219 ot relay215 energicces secondary magnet SM, and the relay 215 and secondarymagnetSM switch B. The restoration of the cut-oil re- Cil i to normal.

lay C() restores the individual switch lV to normal.

The subscriber ll restoring his receiver upon its switchhool interruptsthe circuit ot the relay JR at the switch hook contacts, causing thesaidrelay to de-energize. The closing of normal contact 285 of relay SRcloses a circuit through the left hand winding ,of the relay 229 which`may be traced Ifrombattery, throughthe leiit hand winding cthe saidrelay 229, alternate contact 286, conductor 287, normal contact 285 andconductor 288 to ground at normal contact 228. Due to the dirferentialconstruction of relay 229, the saidrelay' neutralizes and restores Theclosing of normal contact 289 of relay 229 closes an energizingcircuitfor the secondary magnet SM', from battery, through said magnet,conductor 290, normal contact 289, contact 291, through the interrupterI to ground. The secondary mag net SM thusk'steps the wipers235, 236 and237 beyond the last setl of contacts in the group, the wipers'thenrestoring to normal from this position'loy spring tension. Therestoration of the relay 229 opens the circuit ofl relay 242 at contact262, and the relay restoring opens the circuit of relay 266 at contact265. ril`he primary olf-normal contacts PON having restored'upon therestoration o'-the switch, the opening ot the contact 248 cle-energizesrelay RC. The relay also brings about the Vcle-energization ot' the4cut-oli relay CO of the line circuit E which is associated with thecalled subscriber E.

All `the apparatusV used in establishing a connection between a callingsubscriber at the substation A and-the called subscriber at thesubstation Ev is now at normal and available for use in establishingother connections. v

Assuming now 'that the subscriber at the called substation E was firstto replace his receiver upon the switch hook, the opening of the switchhook contacts atvthe substation E brings aboutv the cle-energization ofthe relay SR. Nothing else happens at this time as the relay IRl isstill maintained energized over the line of the calling' substation A.The calling subscriber at' the substation A replacing his receiverinterrupts the circuit of the impulse relay IR at the switch hookcontacts. The relay IR deenergizing closes a circuit 'l'or the lett handwinding of relay 229, causingthe said relay to cle-energize, ashereinbetore described. rlhe restoration of the individual switch B,first selector C and connector D is the same as previously describedfrom this point on. Should the called subscriber E tail to replace hisreceiver upon the switch hook after the conif'ersation is terminated,the replaccontinued energization of the relay SR, thus holding thecontact 285 of said relay in its alternate position preventing thedifferential wound relay 229 from restoring to normal, and closingtheenergizing circuit for the secondary magnet Sil/l. The relay 2230energizes when the line relay IR drops back but is immediately restoredto normal, due to the closure oi' an energizing circuit through thelower winding of the said relay 230, which may be traced from battery,through the said lower winding, conductor 232, alternate` Contact 285,conductor 288 to ground at alternate contact 228 of the now restoredimpulse relay IR. Relay 230 being difierentially wound, restores tonormal and the closing or normal contact 295 ot the said relay 23()places a ground upon the private contact of the connector D over acircuit which mayy be traced from ground at contact 248, conductor 247,normal contact 243 of relay 280, conductor 246, alternate contact 245,normal contact 295, alternate contact 296 ot' the secondary off-normalcontacts SON', to the private'contact 220. The placing of this busyVpotential upon lthe private contact prevents any tirst selector switchC Afrom selecting thecontacts of this busy connector.

Called rZine busy.

Assumingnow that the called line is busy, the operationoi' the circuitis the same up to and including the time that the relay TR momentarilyenergizes, The line being busy, the private contact 250 has a groundconnected to it, and it thus closes a locking circuit for the test relayTR 'rom battery, through the winding of the said relay,` its alternateContact 255, conductor 256, and the wiper 235 to the groundedcontact`250. Alternate contact 297 of the test relay TR remains closedand connects the busy signal BB tothe calling line to transit signal toA,

lll() llU CII

Lac-9,5m

thus notifying the subscriber of the busy condition of the calledsubstation E, Relay RC is also energized when connection is made to abusy line to prevent an application of ringing current from beingapplied to the called line if the called line should become idle beforethe connector D is disconnected from the bank contacts of a called`subscribers line.` The relay RC upon energizing locks up through its ownmake-before-break contacts 277 and 279 to ground at alternate contact248. rlhe calling subscribe er now replaces his receiver, bringing aboutthe de-energization of the impulse relay 1R', and the relay Hlrestoring, opens the circuit of the relay T ofthe first selector C,which, as previously described, bringsy about the release of the iirstselector C and theindividual switch B. The relay 1R cle-energizing,restores relay 229, (since `the relay Sil has not been energized) and bythe closing of circuit through. the left hand winding of said relay 229,the closing `of contact 289 now connects secondary magnet SM andiuterrupter l, and the connector restores to normal by spring tension..lhe primary oit-normal contacts PON and ,secondary off-normal contactsSON are also restored,`and all the apparatus used is now at normal andavailable for use in establishing,

other connections.

While 1 have shown a system of 1,000 capacity, it is to be understoodthat by inserting second selectors, the system may be increased to a10,000 system, etc.

From the foregoing it is at once apparent that I have so arranged thecombined line and test relay of my individual switch that the said relaywill operate very eiciently when energized over a subscribers linecircuit, due to the fact that the two windings of this relay areconnected in series when so actuated and the windings are of the rightresistance to operate most efficiently, and when the relay is used fortesting purposes only its one winding is connected in circuit, whichwinding is of the right resistance to permit a very eiiicient operationof this relay under these conditions, thereby permitting the motormagnet of the switch to operate at a very high rate of speed.

While l have described my invention operating in connection with a wellknown system, 1 do not wish to be limited to this eX- act disclosure asmy invention may be applied to other systems without departing from thespirit of' the invention, and l, therefore, do not wish to be limited tothis exact disclosure but aim to cover all such changes andmodifications as come within the spirit and scope of the appendedclaims.

What 1 claim as new and desire to secure by United States Letters Patentis:`

1. A telephone system including an auto matic switch, a motor magnet forsaid switch, a double wound line relay for controlling said motormagnet, an initial energizing circuit for said line relay including thetwo windings thereof in series, a second circuit for said relayincluding one winding thereof and a contact ofsaid motor magnet, and acircuit for said motor magnet including a contact of said line relay.

2.1@ 'telephone system including an automatic switch provided with acontact maker, motor mechanism for controlling said contact maker, adouble wound relay, an initial energizing circuit for said relayincluding the two windings thereof in series, a second circuit for saidrelay including one winding thereof and a contact controlled by saidmotor mechanism, and a circuit for said motor mechanism including acontact controlled by said relay. i

3, A telephone system including an auto matic non-restoring trunkingswitch, a motor magnet for said switch, a combined test and line relayfor controlling said motor magnet, a cut oiflrelay for said switch, aninitial energizing circuit for said first relay including contactscontrolled by said cut oil' relay, and a second circuit for said testrelay including a contact of said motor magnet and a second contact ofsaid cutoff relay.

l. A telephone system including a `nonnumerical lnon-restoring switch,Ava `double wound test relay and a driving magnet for said switch, acircuit for said test relay including the two windings thereof and acontact of said driving magnet, and a circuit for said driving magnetincluding a contact of said test relay.

5. A telephone system including a nonrestoring automatic switch providedwith a contact maker, a motor magnet for actuating said contact maker, adouble wound test relay fer said switch, an initial energizing circuit:for said test relay including the two windings thereol in series, asecond circuit forsaid test relay including only one winding thereof anda contact of said motor magnet, and a circuitfor said motor magnetincluding a Contact of said relay and said contact maker.

6. A telephone system including a nonrestoring automatic switch, adouble wound relay, a motor magnet, and a cut off relay for said switch,an initial energizing circuit for said double wound relay includingthetwo windings thereof in series, a second circuit 4for said double woundrelay including a contact of said motor magnet and a contact of said cutoif relay, a circuit for said moto-r magnet including a contact of saiddouble wound relay, and a circuit for said cut o relay including acontact of said double wound relay.

` 7. A telephone system including an automatic switch, a motor devicefor said switch,

test Contact, a double wound relay for controlling the said motordevice, an energizing circuit for said double wound relay includ ing thetwo windings in series, a second circuit for said relay including oneWinding thereof and an armature contact controlled by said 4motor deviceand said test Contact, and a circuit for said motor device including acontact controlled by'said double wound relay and said test Contact.

8. telephone system including a subscribers telephone line, a. trunlringswitch for said line, trunk lines extending from said switch, activecontacts for said switch always in engagement with some one of saidtrunk lines, Whicl'i trunk line is the one last employed by said switchfor extending a connection therefrom, a double wound relay for saidswitch, a motor device for actuating said active contacts, Ineans forclosing a parallel circuit for said relay and said motor device wherebyif one or said active contacts is in engagement with a busy passivecontact said motor magnet will be operated to advance said activecontacts, While if said active Contact is in engagement with an idlepassive contact said relay is cle-energized to cause said subscrihersline to be connected with the engaged trunk line.

9. A telephone system including a sub scribers line, aswitch individualthereto, a double-wound relay for Said switch, a motor magnet for saidswitch, an energizing circuit for said doublewound relay including thetwo windings thereof, a second test circuit for said double-wound relayincluding only one winding thereof and a contact of said motor magnet,and a circuit for said motor magnet including` a Contact of the saiddouble-wound relay.

10. A telephone system including a nonnumerical trunk switch, adouble-Wound line relay therefor, a motor magnet therefor, a circuitincluding the two windings of said line relay in series, a secondcircuit for said relay including one winding of the same and a. Contactof said motor magnet, and a circuit for said motor magnet including acontact of said relay.

l1. A telephone system including a nonnumerical non-restoring trunkswitch, a

, double-wound relay and a motor magnet for said trunk switch, a circuitfor said relay including the two windings thereof in series, a secondcircuit for .said relay including one win-ding of the same and a switchContact of said motor magnet, and a circuit for said motor magnetincluding a Contact controlled by said relay.

Signed by Ine at Chicago in the county of Cook and State of Illinois,this 12th day of February, 1919.

HARRY H. IDE.

